The present invention relates to a novel use of zinc N-acetyltaurinate.
Zinc N-acetyltaurinate belongs to the family of taurine derivatives having improved neuromuscular activity, which are described in patent FR 2 384 751. It has now been found, surprisingly, that zinc N-acetyltaurinate (ATA-Zn) can be used for preventing and/or treating diseases with lipofuscin accumulation.
Lipofuscin accumulation can be due in particular to aging or to oxidative stress.
Aging is constituted of a collection of functional modifications which gradually decrease the ability of an individual to maintain his or her physiological equilibrium. One of the manifestations of aging is the accumulation, in the tissues, of lipofuscin, which is an autofluorescent, nondegradable substance; it constitutes the major mark of aging.
Oxidative stress (or oxidizing stress) is an attack on the cells and tissues resulting from a dysregulation of the oxidation reactions in the cells, which leads to the formation of toxic substances, such as free radicals (or reactive oxygen species (ROS)). Oxidative stress can affect all tissues and metabolisms, and participate in aging and in a large number of pathological conditions, such as cardiovascular diseases (atherothrombosis), cancers, inflammatory diseases, metabolic diseases (diabetes mellitus, obesity) and degenerative diseases, such as Alzheimer's disease, Parkinson's disease, cataracts or age-related macular degeneration. Age-related macular degeneration (ARMD) is the most common cause of partial-sightedness in industrialized countries among adults over the age of 55. It manifests itself through a thickening of the macular zone of the retina or atrophy of this zone, and sometimes through bleeding (Opthal, Physiol. Opt. 2003, 23:383-399 and Optometry in practice, vol. 5 (2004) 15-32).
Zinc is very concentrated in the ocular tissues, in particular in the retina and in the pigmentary epithelium. It acts as a cofactor for antioxidant enzymes (retinal catalase and dehydrogenase).
Antioxidants, such as vitamins C and E, carotenoids and zinc can limit the risks of progression of age-related macular degeneration.
In particular, it has been demonstrated that zinc plays an important role in maintaining normal ocular functions and that the use of zinc as a food supplement can reduce the aging process in mice (Journal of the American college of nutrition, 2001, vol. 20, No. 2, 106-118). It is also known that zinc appears to have a fundamental role in the prevention of diabetes mellitus and complications thereof. (Li X et al. Diabetes and methallothionein. Mini-Reviews in Medical Chemistry 2007; 7:761-768).
However, the use of zinc as a food supplement should be considered with care since an excess of zinc can lead to toxic effects.
In addition, studies have shown that taurine interacts closely with zinc in the development of the retina in rats (J. Nutr. 1997, June; 127(6):1206-13) and that taurine, as a food supplement, increases zinc absorption via the fibroblasts (Biometals, 1994, 7, 237-243).